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<H1 class="no-header">form_driver 3x</H1>
<PRE>
<STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>                                                <STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>form_driver</STRONG>, <STRONG>form_driver_w</STRONG> - command-processing loop of the form system


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>form_driver(FORM</STRONG> <STRONG>*</STRONG><EM>form</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>c</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>form_driver_w(FORM</STRONG> <STRONG>*</STRONG><EM>form</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>c</EM><STRONG>,</STRONG> <STRONG>wchar_t</STRONG> <EM>wch</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>

</PRE><H3><a name="h3-form_driver">form_driver</a></H3><PRE>
       Once a form has been posted (displayed), you should funnel input events
       to it through <STRONG>form_driver</STRONG>.  This routine has three major input cases:

       <STRONG>o</STRONG>   The input is a form navigation request.  Navigation  request  codes
           are constants defined in <STRONG>&lt;form.h&gt;</STRONG>, which are distinct from the key-
           and character codes returned by <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.

       <STRONG>o</STRONG>   The input is a printable character.   Printable  characters  (which
           must  be  positive,  less  than  256)  are checked according to the
           program's locale settings.

       <STRONG>o</STRONG>   The input is the KEY_MOUSE special key  associated  with  an  mouse
           event.


</PRE><H3><a name="h3-form_driver_w">form_driver_w</a></H3><PRE>
       This  extension  simplifies  the  use  of  the forms library using wide
       characters.  The input is either a key  code  (a  request)  or  a  wide
       character returned by <STRONG><A HREF="curs_get_wch.3x.html">get_wch(3x)</A></STRONG>.  The type must be passed as well, to
       enable the library  to  determine  whether  the  parameter  is  a  wide
       character or a request.


</PRE><H3><a name="h3-Form-driver-requests">Form-driver requests</a></H3><PRE>
       The form driver requests are as follows:

       <STRONG>Name</STRONG>               <STRONG>Description</STRONG>
       ---------------------------------------------------------------------
       REQ_BEG_FIELD      Move to the beginning of the field.
       REQ_BEG_LINE       Move to the beginning of the line.
       REQ_CLR_EOF        Clear to end of field from cursor.
       REQ_CLR_EOL        Clear to end of line from cursor.
       REQ_CLR_FIELD      Clear the entire field.
       REQ_DEL_CHAR       Delete character at the cursor.
       REQ_DEL_LINE       Delete line at the cursor.
       REQ_DEL_PREV       Delete character before the cursor.
       REQ_DEL_WORD       Delete blank-delimited word at the cursor.
       REQ_DOWN_CHAR      Move down in the field.
       REQ_DOWN_FIELD     Move down to a field.
       REQ_END_FIELD      Move to the end of the field.
       REQ_END_LINE       Move to the end of the line.
       REQ_FIRST_FIELD    Move to the first field.
       REQ_FIRST_PAGE     Move to the first page.
       REQ_INS_CHAR       Insert a blank at the cursor.
       REQ_INS_LINE       Insert a blank line at the cursor.
       REQ_INS_MODE       Enter insert mode.
       REQ_LAST_FIELD     Move to the last field.
       REQ_LAST_PAGE      Move to the last field.
       REQ_LEFT_CHAR      Move left in the field.
       REQ_LEFT_FIELD     Move left to a field.
       REQ_NEW_LINE       Insert or overlay a new line.
       REQ_NEXT_CHAR      Move to the next char.

       REQ_NEXT_CHOICE    Display next field choice.
       REQ_NEXT_FIELD     Move to the next field.
       REQ_NEXT_LINE      Move to the next line.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_WORD      Move to the next word.
       REQ_OVL_MODE       Enter overlay mode.
       REQ_PREV_CHAR      Move to the previous char.
       REQ_PREV_CHOICE    Display previous field choice.
       REQ_PREV_FIELD     Move to the previous field.
       REQ_PREV_LINE      Move to the previous line.
       REQ_PREV_PAGE      Move to the previous page.
       REQ_PREV_WORD      Move to the previous word.
       REQ_RIGHT_CHAR     Move right in the field.
       REQ_RIGHT_FIELD    Move right to a field.
       REQ_SCR_BCHAR      Scroll the field backward a character.
       REQ_SCR_BHPAGE     Scroll the field backward half a page.
       REQ_SCR_BLINE      Scroll the field backward a line.
       REQ_SCR_BPAGE      Scroll the field backward a page.
       REQ_SCR_FCHAR      Scroll the field forward a character.
       REQ_SCR_FHPAGE     Scroll the field forward half a page.
       REQ_SCR_FLINE      Scroll the field forward a line.
       REQ_SCR_FPAGE      Scroll the field forward a page.
       REQ_SCR_HBHALF     Horizontal scroll the field backward half a line.
       REQ_SCR_HBLINE     Horizontal scroll the field backward a line.
       REQ_SCR_HFHALF     Horizontal scroll the field forward half a line.
       REQ_SCR_HFLINE     Horizontal scroll the field forward a line.
       REQ_SFIRST_FIELD   Move to the sorted first field.
       REQ_SLAST_FIELD    Move to the sorted last field.
       REQ_SNEXT_FIELD    Move to the sorted next field.
       REQ_SPREV_FIELD    Move to the sorted previous field.
       REQ_UP_CHAR        Move up in the field.
       REQ_UP_FIELD       Move up to a field.
       REQ_VALIDATION     Validate field.

       If  the  second argument is a printable character, the driver places it
       in the current position in the current field.  If  it  is  one  of  the
       forms requests listed above, that request is executed.


</PRE><H3><a name="h3-Field-validation">Field validation</a></H3><PRE>
       The  form  library  makes  updates  to  the window associated with form
       fields rather than directly to the field buffers.

       The form driver provides low-level control over  updates  to  the  form
       fields.   The  form driver also provides for validating modified fields
       to ensure that the contents meet whatever  constraints  an  application
       may attach using <STRONG>set_field_type</STRONG>.

       You  can  validate  a  field  without  making  any  changes to it using
       <STRONG>REQ_VALIDATION</STRONG>.  The form driver also validates a field in these cases:

       <STRONG>o</STRONG>   a call to <STRONG>set_current_field</STRONG> attempts to move to a different field.

       <STRONG>o</STRONG>   a call to <STRONG>set_current_page</STRONG> attempts to move to a different page  of
           the form.

       <STRONG>o</STRONG>   a request attempts to move to a different field.

       <STRONG>o</STRONG>   a request attempts to move to a different page of the form.

       In each case, the move fails if the field is invalid.

       If  the  modified  field  is valid, the form driver copies the modified
       data from the window associated with the field to the field buffer.


</PRE><H3><a name="h3-Mouse-handling">Mouse handling</a></H3><PRE>
       If the second argument is the KEY_MOUSE  special  key,  the  associated
       mouse  event  is translated into one of the above pre-defined requests.
       Currently only clicks in the user window (e.g., inside the form display
       area or the decoration window) are handled.

       If you click above the display region of the form:

          a REQ_PREV_FIELD is generated for a single click,

          a REQ_PREV_PAGE is generated for a double-click and

          a REQ_FIRST_FIELD is generated for a triple-click.

       If you click below the display region of the form:

          a REQ_NEXT_FIELD is generated for a single click,

          a REQ_NEXT_PAGE is generated for a double-click and

          a REQ_LAST_FIELD is generated for a triple-click.

       If you click at an field inside the display area of the form:

          <STRONG>o</STRONG>   the form cursor is positioned to that field.

          <STRONG>o</STRONG>   If  you  double-click  a field, the form cursor is positioned to
              that field and <STRONG>E_UNKNOWN_COMMAND</STRONG> is returned.  This return value
              makes sense, because a double click usually means that an field-
              specific action should be returned.  It is exactly  the  purpose
              of  this  return  value  to  signal that an application specific
              command should be executed.

          <STRONG>o</STRONG>   If a translation into a request was  done,  <STRONG>form_driver</STRONG>  returns
              the result of this request.

       If  you clicked outside the user window or the mouse event could not be
       translated into a form request an <STRONG>E_REQUEST_DENIED</STRONG> is returned.


</PRE><H3><a name="h3-Application-defined-commands">Application-defined commands</a></H3><PRE>
       If the second argument is neither printable nor one of the  above  pre-
       defined form requests, the driver assumes it is an application-specific
       command and returns  <STRONG>E_UNKNOWN_COMMAND</STRONG>.   Application-defined  commands
       should  be  defined relative to <STRONG>MAX_COMMAND</STRONG>, the maximum value of these
       pre-defined requests.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       <STRONG>form_driver</STRONG> returns one of the following error codes:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or out-of-range argument.

       <STRONG>E_BAD_STATE</STRONG>
            Routine was called from an initialization or termination function.

       <STRONG>E_NOT_POSTED</STRONG>
            The form has not been posted.

       <STRONG>E_INVALID_FIELD</STRONG>
            Contents of field is invalid.

       <STRONG>E_NOT_CONNECTED</STRONG>
            No fields are connected to the form.

       <STRONG>E_REQUEST_DENIED</STRONG>
            The form driver could not process the request.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred (see <STRONG>errno(3)</STRONG>).

       <STRONG>E_UNKNOWN_COMMAND</STRONG>
            The form driver code saw an unknown request code.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,   <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>,   <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>,    <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>,
       <STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>, <STRONG><A HREF="form_variables.3x.html">form_variables(3x)</A></STRONG>, <STRONG><A HREF="curs_getch.3x.html">getch(3x)</A></STRONG>.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       The  header  file  <STRONG>&lt;form.h&gt;</STRONG>  automatically  includes  the  header files
       <STRONG>&lt;curses.h&gt;</STRONG>.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These routines emulate the System  V  forms  library.   They  were  not
       supported on Version 7 or BSD versions.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.



                                                               <STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-form_driver">form_driver</a></li>
<li><a href="#h3-form_driver_w">form_driver_w</a></li>
<li><a href="#h3-Form-driver-requests">Form-driver requests</a></li>
<li><a href="#h3-Field-validation">Field validation</a></li>
<li><a href="#h3-Mouse-handling">Mouse handling</a></li>
<li><a href="#h3-Application-defined-commands">Application-defined commands</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-AUTHORS">AUTHORS</a></li>
</ul>
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